How to find the right keymap to change on addon registration?
Are you after one of these, e.g. rotate?

&gt;&gt;&gt; C.window_manager.keyconfigs.user.keymaps['Transform Modal Map'].keymap_items[5].propvalue
'ROTATE'


I'm pretty sure there's only one modal map for all transform operators (and not changable with python).

import bpy
wm = bpy.context.window_manager
keymap = [k for k in wm.keyconfigs.user.keymaps['Transform Modal Map'].keymap_items if k.type == 'G'] #k.propvalue=="TRANSLATE"]
modal_translate = keymap[0] if len(keymap) &gt; 0 else None
print("\n", modal_translate)
for attr in dir(modal_translate):
    if not attr.startswith("_"):
        val = getattr(modal_translate, attr)
        if type(val) in {int, float, str, bool}:
            print("\t", attr, "=", val)

"""
 &lt;bpy_struct, KeyMapItem("")&gt;
         active = True
         alt = False
         any = False
         ctrl = False
         id = 5
         idname =
         is_user_defined = False
         is_user_modified = False
         key_modifier = NONE
         map_type = KEYBOARD
         name =
         oskey = False
         propvalue = TRANSLATE
         shift = False
         show_expanded = False
         type = G
         value = PRESS
"""


But note that you can't provide an operator name in modal maps. Only the predefined modal operations can be set (propvalue).